The national wind/photovoltaic/energy storage/transmission demonstration project is the first pilot project of the State Grid Corporation of China for constructing a strong smart grid, with “grid-friendly” new energy generation as the goal and “advancement, flexibility, demonstration and economical efficiency” as features, and the project is a renewable energy source comprehensive demonstration project having the largest scale in the world at present and integrating wind power generation, photovoltaic power generation, energy storage and transmission projects.
Wherein, the national wind/photovoltaic/energy storage/transmission demonstration project (first stage) plans to construct wind power generation 100 MW, photovoltaic power generation 40 MW and energy storage devices 20 MW (including a 14 MW lithium iron phosphate energy storage system, a 2 MW all-vanadium flow battery energy storage system and a 4 MW sodium-sulfur battery energy storage system). With the continuous development of lithium batteries and the integration technology thereof, it has become a feasible solution that a lithium battery energy storage power station is used for achieving smooth wind-photovoltaic power output, tracking planned power generation, system frequency modulation participation, peak clipping and valley filling, transient active output emergency response, transient voltage emergency support and other applications, one of the key issues is to master the energy management technology of the large-scale multi-type battery energy storage power station and a coordinated control method of multi-type large-capacity battery energy storage machine sets.
From the perspective of battery energy storage, over-charge and over-discharge will influence the service life of the battery. Therefore, it is necessary to monitor the battery charge state, reasonably allocate total power demands in the energy storage power station and control the battery charge state within a certain range.
The multi-type energy storage systems can be approximately divided into power type energy storage systems and energy type energy storage systems. At present, very few patents, literature, technical reports and the like with respect to real-time total power control and energy management based on megawatt multi-type battery energy storage power stations are available, the core technology of comprehensive control and grid-connected operation of the large-scale multi-type battery energy storage power stations need to be researched and explored in depth, and the key problems of coordinated control and energy management of the large-scale multi-type battery energy storage power stations need to be solved. In the existing power control and energy management methods of large-scale battery energy storage systems/power stations, the charge and discharge rate properties of the energy storage batteries cannot be included in constraint conditions generally to carry out energy management, therefore, sometimes, the advantage of complementary properties of different types of energy storage systems cannot be fully embodied, and the service lives of the batteries are influenced, etc.